Why Is the Earth Like a Magnet?

Earth behaves like a magnet because the molten iron core of Earth interacts with the movement of electrons on the surface of the planet. Use a compass to determine the direction of the north and south magnetic poles with information from a math and science teacher in this free video science lesson.

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Video Transcript

Hi, I'm Steve Jones, and I'm going to explain why the earth is like a magnet. Well, we've often seen this diagram in books, where you seem to have a big bar magnet, somehow buried inside the earth. The earth isn't like that at all. The earth contains several layers, but the center of the earth is the core. The core is molten, and is molten iron material, and it seems to be from there, that the earth creates its magnetism, and the reason it behaves like a magnet, is because magnetism is about the movement of electrons. It's created by the movement of electrons, and electrons are in every material. The net result of this is that, at the surface of the earth, we have a magnetic field, and the magnetic field is concentrated fairly vertically, at the magnetic poles. In fact, it's vertical at the magnetic poles, and it's horizontal, because don't forget when we stand here, that is the vertical, so this is horizontal, around the equator, but the poles, there's the vertical, and the field lines are vertical, so this is why the earth is like a magnet, because of course, when we take anything magnetic, these magnetic field lines, react with the magnetic object. If you have two magnetic fields, and put them together, they react. They behave differently, and therefore, putting a magnetic object like a compass, that is like a, little bar magnets say, and let's say we put, we suspend it, then we'll find that the north end of the magnet, points towards the north, which means that the earth is actually a south pole, at the north, a south magnetic pole at the north. This is the magnetic pole, which is not the same as the geographic pole. It's about eight degrees different, so that is basically why, the earth behaves as a magnet.